A wideband CPW-fed microstrip antenna at millimeter-wave frequencies

This paper presents a CPW-fed aperture-coupled micromachined microstrip antenna operating at 94 GHz. The design consists of two stacked silicon substrates: (1) the top 200 /spl mu/m silicon substrate, which carries the microstrip antenna, is micromachined to improve the radiation performance of the antenna, and (2) the bottom 100 /spl mu/m silicon substrate, which carries the feed CPW line. The performances of this new antenna are compared to the ones obtained with a microstrip-fed aperture-coupled micromachined microstrip antenna designed by some of the authors and published previously. It is demonstrated that a wider bandwidth and a less sensitive input impedance versus the fabrication process accuracy are obtained with the new design presented in this paper. The measured return loss is -27 dB at 94 GHz with a 10-dB bandwidth greater than 30%. The CPW-fed aperture-coupled micromachined microstrip antenna is an efficient solution to the vertical integration of antenna arrays at millimeter-wave frequencies.